When I first bought my wonderful Janome sewing machine I went to a 'Getting to Know Your Machine' session. Before we even took the covers off our machines we were given a Schmetz Needle Guide. I hadn't really given a great deal of thought to needles, other than that I knew it was good practice to change needles regularly in order to maintain good stitch quality. From the needle Guide I learnt all about the anatomy of a needle. How can something so small have so many different parts? As the Needle Guide is so informative you can view it by clicking here
So it's worth remembering that in addition to using good quality thread on your projects your needles ought to be changed regularly as well. Happy quilting!